NGK Spark plugs for 350?

I'm looking at the NGK Iridium spark plugs on the internet, and they say they make them for 350's. My question is are these better than the AC Delco Platinum and will they help me pass emissions better since I'm kinda on the edge right now?

Not too long ago, put on a new cap and rotor about 9 months ago, new MSD ignition coil about 6 months ago. Spark plugs and plug wires were about a year and a half ago. I know the catylic is 17 years old, but I put it on a gas analyzer and it passes, but just barely. I gaped the plugs to .060 instead of .035 and it made an improvement emission wise.

I've always liked NGK plugs, I use them in all my small motors and they are just awesome, extremely hard to foul, so I figured the Iridium's for my chevy would be even better.